Automatic stop for extrusion presses



Octo 23,1934. M, A. FAIR 1,977,824

AUTOMATIC sToP FORv ExTRUsIoN PRESSES Filed May 27. 1933 3 Sheets-Sheet l INVENTOR .Nara/s Af/f' f ATTORNEY Otta 23, 1934. M ph FAIR 1,977,824

AUTOMATIC STOP FOR EXTRUSION PRESSES Filed May 27. 1933 SSheets-Sheet 2 l. i Z7 Z7 27/ 4, ZZ, `Z/

llllllllll A TTORNE Y OCLAZS, 193.4. Ml A FAIR 1,977,824

AUTOMATIC s-ToP FOR EXTRusIoNrREssEs Filed May 27, 1955 s sheetssheet s IN VENT OR ./Varc//s A Fa/f BY A A ORNEY patented Oct. 23, 1934 UNrrlsD STATES PTNT FFICE ATOMATIC STOP FOR EXTRUSION PRESSES Application May` 27, 1933, Serial No. 673,242

14 Claims. (Cl. 207-9) The invention relates to automatic stop mechanism for presses and is directed to the provision of such mechanism which is 'adapted to presses used for the extrusion of thin-walled collapsible tubes from blanks or slugs.

Presses of this type operate by compressing the slug of metal which is placed in a recess in a female die member, a punch descending into the recess and compressing the metal slug so that the' metal flows or squirts-upwardly between the punch and the walls of the die recess surrounding the punch, thus forming a thin-walled tube. The operation just described is that which is known to the art as impact or inverse'extrusion and represents the commercial process of manufacturing collapsible tubes 'of such metals as aluminum and tin.

After the completion of the extrusion step the tube must be removed from the punch to which it often clings tenaciously, and various means have been devised to accomplish this purpose. Such means have not proved perfectly reliable, but on the contrary it not infrequently occurs that the tube stripping means fails,y with the consequence that on the next succeeding downward movement of the punch the previously extruded tube is carried downwith it into the die recess and against the next'extrusion slug, leaving no clearance between the punch and the walls of the die recess.

results in failure or breakage of thepunch or die, with consequent expensey of repair or replacement and delay due to temporary -shut down of the press.

It also sometimes occurs that the extruded tube is stripped from the punch properly but fails to be removed from the die. The reason for this will be apparent when it is understood that the means for stripping the tube from the punch are 40 sometimes associated with the die or form a part of the die itself, so that the tube is held in place in the die as the punch moves upwardly on its return stroke. Supplementary devices such as a knock-out pin and a blast of air from.

The present invention is directed to the elimi '55 nation of these hazards and is designed to auto- This condition occasionally vmatically stop the press upon failure. of tube stripping devices to properly function. 'I'he seriousness of the problem thus presented will be better appreciated when it is understood that presses of the type .described operate at such a rate of speed that it is impossible for an operator to observe the failure of the tube stripping devices to function and stop the press in time to avert the damage. Moreover, collapsible tube extrusion presses are frequently designed to operate automatically and independently of the attention of an operator, the feeding of the slugs as well as the removal of the extruded tube being entirely automatic.

It is accordingly an object of my invention to provide mechanism for automatically stopping the press upon failure of the tube stripping devices to serve their intended purpose. It is a further object to providesuch an automatic stop mechanism which will stop the press upon failure of either (1) the means for stripping the tube from the punch or (2) the means for removing the extruded tube from the die recess subsequent to retraction of the punch.

A particular object is the 'provision of automatic stop mechanism responsive to failure of either of the above identified tube stripping means to either throw a breaker switch in the press motor circuit or to disengage a drive clutch and apply a brake to stop the press. In the drawings, which illustrate a preferred embodiment of the invention:

Fig. 1 is an elevational view of the punch and die of an extrusion press with associated structure and showing the application of my invention thereto; Fig. 2 is a horizontal sectional view taken on the line II-II of Fig. 1; Fig. 3 is a vertical sectional view of the punch, die and associated structure, the parts being shown to a somewhat enlarged scale; and Fig. 4 is a schematic diagram in perspective illustrating the co-operation of the electrical circuit closing means with suitable means to disengage a drive clutch and apply a brake to stop the press.

The anvil or bed of the press is indicated generally by the reference numeral 1. The press slide 2 carries the punch 3 which is mountedfor vertical movement toward and away from the die 4 in a straight line. In Fig. 1 the shuttle and blank feed slide are indicated generally by the reference numeral 5. This device will subse- .quently be more fully described in connection brackets being disposed at such a height with respect to the face of the die 4 that the plate or bar 9 which normally rests thereon during the extru- Fig. 2. The plate or bar 9 is apertured adjacentl each end to freely receive a pair of adjustable lifting rods 11 which are suspended from the press slide 2 by means of angle brackets 12. The lifting rods 11 are headed or provided with nuts 13 at their lower ends and at their upper ends are adjustably mounted in `the brackets 12 as by means of the nuts 14, 15, the upper ends of rods 11 being threaded over aconsiderable distance as at 16 to allow for adjustment.

' The plate or bar 9 is provided with. a number of spring clips or fingers 17 arranged to bear lightly against the punch 3. These spring clips 1'7 are so adjusted as to allow the naked punch 3 to slide freely up and down with respect to the plate 9 without disturbing its position on the brackets 6. The bifurcated ends 10 of brackets 6 are separated sumciently to allow the headed ends or nuts \13 on the lifting rods 11 to pass therebetween as the press slide moves upwardly, the nuts 13 engaging the under side of the plate 9 and lifting it into the vposition indicated by the dotted lines 9 in Fig. 1. This represents the position of the plate when the press slide is in its uppermost position.

An electric switch 18 is secured to one of the columns of the press in fsuch a position that the trip arm 19 thereof is disposed in the path of movement of the plate 9 just above its normal uppermost position at 9. The leads 20 from the switch 18, which will preferably be of the type known as a mercury switch, are connected to a source of power and to a solenoid control which is adapted to vdisengage a clutch in the drive shaft of the press and apply a brake when the switch 18 is thrown. A

When punch 3 is in its uppermost positionits lower end is above the level of the horizontal/portions 8 of the angle brackets 6. It is the function of the lifting rods 11 to prevent the plate 9 from dropping off the end of the punch whenit is lifted above the level of the horizontal extensions 8. As

the punch travels downwardly the plate 9 comes to rest on the -horiz'ontal extensions 8 of the brackets and the punch continues on downwardly, entering the recess of the die 4'and extruding a tube. Let us assume that upon the upward return stroke of the punch 3 the tube stripping device fails to function and the extruded tube clings to the punch. When the walls of the clinging tube come into contact with the spring clips 17 on the plate 9 a yrestraint is placed upon further free sliding movement between the punch 3 and plate 9 with the result that the plate is lifted beyond its normal uppermost position 9 so that it strikesY 'the trip lever 19-of the switch 18, serving to actuate the instrumentalities for stopping the press which have previously been described.

Referring moreparticularly to Fig. 3, there is shown a shuttle and blank feed sli e 21 (forming a part of the structure hereina ve 4designated generally by the reference numeral 5) ."-jThere is also shown a suitable tube stripping device. It

. willbe understood that the design and operation Aof the tube stripping device do not form a part of my invention. Any suitable means may be employed for this purpose. I have chosen for purposes'of illustration 'a tube stripping means simi- Y position indicated in Fig. 3, preventing the proper lar to that illustrated'in the patent to Kinkead 1,722,634. 'I'his means consists of the neck-engaging groove or recess 22 formed in the tapering recess 23 of the die cavity. When the tube is extruded there is formed on the neck of the tube a small shoulder extending into the annular groove 22 which serves to hold the tube positively in the die during the upward movement of the punch, thus stripping the formed tube therefrom. After this, the block 24 rises, lifting the knockout 25 and bringing the knock-out pin 26 against the neck of the formed tube, lifting it bodily out of the die cavity. As this occurs, the metal of the rib in the recess 22 flows outwardly and conforms with the tube neck surface previously formed in the tapering portion 23 of the die recess. A s the tube clears thevtop of the die it is removed by any suitable means, as for example a blast of air issuing from a nozzle 27 which blows the tube to one side into a suitable receptacle.

The said slide or shuttle 21 is arranged for movement toward and away from the edge of the die recess serving to deposit a blank or slug 28 in the recess at the' end of its forward movement.

Mounted on the feed slide 21 in a position above 100 and slightly in advance of the leading edge of the blank which is being fed into the die recess is an electrical contact member'29. Contact member 291s insulated from the feed slide as by the fibre insulation 29. A lead wire 30, extending from the contact member 29, is connected to the solenoid which'has been referred to hereinabove.

Let us assume that at the conclusion of the extruding operation the punch 3 has been withdrawn from the die recess leaving the tube 31 in the position shown in Fig. 3; assume further that the knock-out pin 26 has been raised by means of the block 24 but that through failure of the knock-out pin 26 to cause the formed tube to completely clear the top of the die or through failure of the air blast from nozzle 27 to remove it the tube 31 is allowed to remain in or above the die recess. The shuttle associated with the blank feed slide 21 now moves toward the die recess (to the left, as viewed in Fig. 3)` to deposit another blank in the die. The knock-out device having failed to remove the tube 31 completely from the recess, it remains, let us say, substantially in the feeding of the succeeding blank 28. However, as the shuttle moves forward to the point where member 29 comes into contact with the walls of the extruded tube 3l, an electric circuit is completed through the walls of the tube 3l, the die 4 and the bed 1 of the press to actuate the aforesaid 130 solenoid, causing release of the clutch in the drive shaft and application of the brake to stop the press. The electrical connections for the automatic stop device are best seen in Fig. 1. The lead 30 extending from contact member 29 is con- 135 veniently connected with one of the leads 20 from the'switch 18 and a lead 31 from the bed 1 of the press is connected with the other lead 20 so that the circuit for the shuttle contactor 29 is ar- Y ranged in -parallel with the circuit for the switch 18, the two circuits being connected with the sourceof power and solenoid control.

Thus., upon failure of either the tube stripping devi'ce or of the knock-out device to function because of binding, jamming, sticking, or for any other reason, an electric circuit will be completed to stop the press and prevent damage to the punch or die.

Fig, 4 illustrates diagrammatically the vdevices hereinabove described, together with suitable clutch and brake actuating mechanism. For simplicity of illustration, the press drive shaft is indicated at 32, this shaft being connected to the clutch 33, pulley 34 and belt 35, and to a suitable source of power. The press slide or crosshead 2 is arranged forreciprocating movement in a vertical direction by a suitable crank 36. The leads 20, 30, 31 are connected to a source of power 37 and solenoid 39. The plunger 40 of the solenoid is connected to a bell crank lever 41 and through suitable linkage 42 to the clutch 33 so that when the plunger 40 of the solenoid is drawn upwardly by completion of the circuit in eith'er of the ways which have been described the clutch shift arm 43 is moved in the direction of the arrow A, disengaging the clutch. The upward movement of the solenoid 40 also serves to apply a brake 44 through the medium of a part of the aforesaid linkage 42. rod 45, which forms a part of the aforesaid linkage 42, is drawn downwardly as indicated by the arrow B, serving to tighten the brake band.

It will be obvious that the press, if electrically driven, may be stopped by the tripping of a breaker switch in the motor circuit, this arrangement serving as a substitute for the mechanical clutch and brake illustrated in Fig. 4. There are other modifications which might be made in the arrangement disclosed, and it will be understood that such modifications as are within the scope of the appended claims are considered to properly fall within the purview of my invention.

I claim:

1. In a collapsible tube extrusion press, a Idie and a punch cooperable therewith to inversely extrude a collapsible tube,means associated with the die for stripping the extruded tube from the punch as said punch is withdrawn from the die, and electrical means responsive to failure of the tube-stripping device to function for stopping the press. f

2. In a collapsible tube extrusion press, a die and a punch cooperable, therewith to inversely extrude a collapsibletube, means associated with Ithe die for stripping the extruded tube from the punch as said punch is withdrawn from the die, a knock-out device for removing the stripped tube from the die, and means for automatically stopping the press upon failure of -the tube-stripping device to function, said last-named means being responsive also to failure of the knock-out device to function.

3. In a collapsible tube extrusion press, a vdie and a punch cooperable therewith to inversely extrude a collapsible tube, means associated with the die for stripping the extruded tube from the punch as said punch is withdrawn from the die, a knock-out device for removing the strippedztube from the die, and means for automatically stopping the press, said last-named means being responsive to failure of said knock-out device to remove the stripped tube from the die.

4. In a collapsible tube extrusion press, a die having a recess to receive an extrusion blank, a punch cooperable with said die recess to inversely extrude a collapsible tube, a shuttle arranged to feed extrusion blanks to said die recess, means associated with the die forlstripping the extruded tube from the punch as said punch is withdrawn from the die, a knock-out device for removing the stripped tube from the die, and means associated with said punch and with said shuttle for automatically stopping the press upon failure of the tube-stripping device tofunction, said last- As plunger 40 is drawn upwardly thel tube from the punch as said punch is withdrawn from the die, a knock-out device for removing the stripped tube from the die, and means associated with said shuttle for automatically stopping -the press, said last-named means being re- -sponsive to failure of said knock-out device to remove the stripped tube from the die.

6. In a collapsible tube extrusion press, a die and a punch cooperable therewith to inversely extrude a collapsible tube, means associated with the die for stripping the extruded tube from the punch as said punch is withdrawn from the die, a member mounted for slidable engagement with said punch, said member being freely slidable with respect to the naked punch and arranged Y to be moved with the punch as said punch is withdrawn from the die, such movement' occurring upon failure of the tube-stripping device to function when the unstripped tube prevents said member from sliding freely with respect to the punch, and means for stopping the press, said movement of said member serving to actuate the press stopping means.

'7. In a collapsible tube extrusion press, a die and a punch cooperable therewith to inversely extrude a collapsible tube, meansassociated with the die for stripping the extruded tube from the punch as said punch is withdrawn from the die, a member closely surrounding said punch `and normally slidable with respect thereto, said mem-` ber being freely slidable with respect to the naked punch and arranged to be moved with the punch as said punch is withdrawn from the die, such movement occurring upon failure of the tubestripping device to function when the unstripped tube prevents said member from sliding freely with respect to the punch, and means for stopping the press, said movement of said member serving' to actuate the press stopping means.

8. In a collapsible tube extrusion press, a die andl a punch cooperable therewith to inversely extrude a collapsible tube, means associated with thedie for stripping the extruded tube from the punch as said punch is withdrawn from the die, a member apertured to allow said punch to pass therethrough, spring clips secured to said memrespect to the naked punch and arranged to be moved with the punch as said punch is withdrawn from the die, such movement occurring upon failure of the tube-stripping device to function when the unstripped tube engages said spring clips thereby preventing said member from sliding freely with respect to the punch, and means for stopping the press, said movement of said member serving to actuate the press stopping means.

9. In a collapsible tube extrusion press, a die and a punch cooperable' therewith to inversely extrude a collapsible tube, means associated with the die for stripping the extruded tube from the punch as said punch is withdrawn from the die,

a member mounted for slidable engagement with be moved with the punch as said punch is withdrawn from the die, such movement occurring upon failure of the tube-stripping deviceto function lwhen the unstripped tube prevents said member from sliding freely with respect to the punch, and means for stopping the press, said means comprising an electrical switch arranged inthe path of movement of said member and adapted to be actuated thereby to operate a solenoid, disengage a clutch in the press driving mechanism, and apply a brake to stop the press.

10. In a collapsible tube extrusion press, a die having a recess to receive an extrusion blank, a punch cooperable with said die recess to inversely extrude a collapsible tube, a 'shuttle arranged to feed extrusion blanks to said die recess, means associated with`the die for stripping the extruded pleted through said extruded tube, said die, and

said contact member, and means for stopping the press, the completion of said'electrical circuit serving to actuate the press stopping means.`

11. In a collapsible tube extrusion press, a die having a recess to receive an extrusion blank, a punch cooperable with said dierecess to inversely extrude a collapsible tube, a shuttle arranged to feed extrusion blanks to said die recess, means associated with the die for vstripping the extruded tube from the punch as said punch is withdrawnl from the die, a knock-out device for removing the stripped tube from the die, and an electrical contact member movable toward and away from said die recess in response to movement of said shuttle, said contact member being arranged in circuit with a solenoid, said :solenoid being adapted to disengage a clutch in the press driving mechanism and apply a brake to' stop the press, said contact member being arranged to approach the edge of the die recess in advance of the blank as the blank is moved toward the die recess during vthe feeding movement of Asaid shuttle, whereby upon failure of said knock-out device to remove the previously extruded tube from the die said solenoid circit is completed through said extruded tube and said die to actuate the press stopping mechanism.

12. In a collapsible tube extrusion press, a die and a punch cooperable therewith to inversely extrude a collapsible tube, means associated with the die for stripping the extruded tube from'the punchas said punch is withdrawn from the die, said punch being arranged for movement toward and away from said die in a straight line during saidextruding and stripping operations, and means for automatically stopping the press,gsaid, last-named meansbeing responsive to failure of the .tube-stripping device to function.

13. In a collapsible tube extrusion press, a die and a punchY cooperable therewith to inversely extrude a collapsible tube, means associated with the die for stripping the extruded tube from the punch as said punch is withdrawn from the die, said punch being arranged for movement toward and away from said die in a straight line during said extruding and stripping operations, a member mounted fox'` slidable engagement with said punch, said member being freely 'slidable with respect to the naked punch and arranged to be moved with the punchas said punch is withdrawn from the die, such movement occurring upon failure of the tube-stripping device to function when` the unstripped tube `prevents said member from sliding freely with respect to thefpunch, and means for stopping the press, said movement of said member serving to actuate the press stopping'means 14. In a collapsible tube extrusion press, a die and a punch cooperable therewith to inverselyextrude a collapsible tube, means associated with the die for stripping the extruded tube from the punch as said punch is withdrawn from the die, a member closely surrounding said punch and slidable with respect thereto, a stationary supporting member secured to a stationary portion of the press and adapted to support said slidable member, a movable supporting member mounted for movement with said punch and arranged during a portion of such movement to lift said slidable member from engagement' with said supporting member to prevent said slidable member from falling off the end of said punch, said slidable member also being arranged for movement with. the punch independently of said movable supporting member as said punch is withdrawn from the die, such last-named movement occurring only upon failure of the tube stripping device to function when theunstripped tube prevents said member from sliding freely with respect to the punch, and means for stopping the press, said last-named movement of 4said member serving to actuate the press stopping means.

MARCUS A. FAIR. 

